Stereotactic
core needle biopsy is a minimally invasive procedure for the diagnosis
of a nonpalpabral breast lesion. Although ultrasound-guided needle biopsies
are less expensive (or 'cost effective', in weasel talk), they are more
operator dependent, with an accuracy between forty-seven and ninety percent.

Stereotactic
core biopsies requires an incision only four millimeters in size, with
a more reassuring accuracy of ninety-eight percent. However, the SCNB has
some drawbacks. When atypical ductal hyperplasia is the diagnosis, a woman
is required to have an excisional biopsy done. About one out of three patients
require a second diagnosis after a stereotactic core needle biopsy. About
two in five patients who had second diagnostic procedures done after the
SCNB were found to have cancer.

Now,
the part you really want to know. How they do it. The patient is positioned
on a table, providing three hundred sixty degree access. The breast is
compressed. Stereotactic x-rays are then taken for targeting within one
millimeter of the lesion. A localizing needle is guided to the precise
location of the lesion by the digital stereotactic x-ray through and incision.
When the needle is in place and verified, a T-fastener is then deployed,
fixing the lesion in place. The position is again verified. The biopsy
begins with further infiltration of a local anesthesia and an extension
of the cut. If the lesion is located deep in the tissue of the breast,
the superficial tissues are moved by a scapula. A cyndrilical cannula is
pushed over the needle while a motorized circular blade cuts the tissue.
It is pushed to the depth of the tumor and it's location verified and the
tumor has been captured by the cannula. A cautery snare cuts across the
deep end of the cannula, and the sample can be removed. A complete mammogram
is taken before the patient is taken out of compression. A x-ray confirms
that the malignant tissue was removed. Then, the patient is rolled into
a supine position for inspection of the biopsy site. Bleeding is common
and easily controlled by cautery, clips, or sutures. There are four cannula
sizes available: five, ten, fifteen and twenty millimeters.